Compositions based on polyvinyl chloride (PVC) and other halogenated polymers, such as chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSPE), are commonly used for many useful articles such as wire or cable insulation, electrical component housings and electrical conductors. Insulated products include residential and commercial building wire; portable power cord and fixture wires; automotive primary (harness) wire; telephone and other communications wires; instrument and appliance wires; motor lead wires, etc. Compositions based on halogenated polymers typically provide required flame resistance, oil resistance, and resistance to environmental factors such as ozone and ultraviolet light to a greater extent than would similar nonhalogenated polymers (e.g., olefin polymers and copolymers). Therefore, the use of compositions based on halogenated polymers in useful products is widespread.
Presently, for example, the wire and cable industry has relied on insulating vinyl halide resins containing heat stabilizers based on lead compounds. Thus, electrically insulating polyvinyl chloride (PVC) compositions usually include dibasic lead phthalate, dibasic lead phosphite, tribasic lead sulfate, or lead stearate, among others, as heat stabilizers. With chlorinated polyethylene or chlorosulfonated polyethylene, litharge and red lead oxide are also used.
On Jun. 22, 1990, Part 261 of CFR 40, Protection of Environment, was amended to include (as Appendix II) Method 1311, Toxicity Characteristic Leaching Procedure (TCLP), as a prerequisite for any solid waste to be landfilled as nonhazardous waste. When tested per Method 1311, the solid waste must yield an extract containing less than 5.0 mg/1 of lead.
Typical lead-stabilized PVC wire and cable compounds yield values of 2 to 10+ mg/1 in this test, often depending on how finely divided the scrap is (round pellets tend to pass, flat flakes or powder tend to fail because of higher surface area per volume). Further, there is much data scatter. A landfill operation is, therefore, typically unwilling to accept values of 2-4 mg/1 as evidence of nonhazardous character. Additives that could reduce the level of lead or other heavy metal extractables from PVC by the TCLP could have great commercial value.